looking for oddball for my tank

I have a pair of HRPs along with some small barbs and am looking for an interesting oddball for the tank. I was thinking Oriental Bichir but having trouble acquiring a small one... then was recommended rope fish but not sure how well that will hold up to my HRPs and don't want something that will stay in hiding.. Any ideas?

I have a zebra knife fish, but it would most likely eat the barbs and does tend to stay out-of-sight. What size tank?